The present invention, in some embodiments thereof, relates to time division duplex communication and, more particularly, but not exclusively, to interfering with time division duplex communication.
In time division duplex (TDD) communication, transmissions by network nodes are separated into different time slots. In some cases, the nodes use different transmission schemes. For example, one node transmits frequency hopping packets whereas a second node transmits fixed frequency packets during their respective allocated time slots.
Time-division duplexing has a strong advantage in the case where there is asymmetry of the uplink and downlink data rates. As the amount of uplink data increases, more communication capacity can be dynamically allocated, and as the traffic load becomes lighter, capacity can be taken away.
In some cases, wideband jamming signals are used to disrupt communication uplink and/or downlink communication. In order to interfere with Node B's reception of transmissions from Node A, a wide band jamming signal is transmitted towards Node B. The jamming signal may be a high bandwidth (BW) noise signal (such as white Gaussian noise) or any other wide band signal (such as actual data or a chirp signal).
One disadvantage of wideband jamming solutions is possible interference to other communication links in the area. Another disadvantage is loss of power, because the power is distributed over the full bandwidth. In addition, jamming solutions do not use a disconnect command and hence can only cause the two nodes to disconnect by raising the bit error rate (BER) in Node B's reception of Node A.
Another approach to this problem is to transmit a pulsed jamming signal during the Node A time slot at all the known frequencies used by Node A in parallel. The disadvantage of the solutions above is still loss of power, as the power is distributed over Node A's entire frequency range. Also, as in the previous solution, this jamming technique does not contain a disconnect command.
Additional background art includes:
                [1] M. Karlsson et al., “Jamming a TDD Point-to-Point Link Using Reciprocity-Based MIMO”, IEEE Transactions on Information Forensics and Security, 12(12), pp. 2957-2970, 11 Jul. 2017.        [2] International Patent Application Publication No. WO 93/26124.        [3] K. Grover et al., “Jamming and Anti-jamming Techniques in Wireless Networks: A Survey”, International Journal of Ad Hoc and Ubiquitous Computing Volume 17 Issue 4, Pages 197-215, December 2014.        [4] International Patent Application Publication No. WO 93/22850.        [5] K. Parlin, “Jamming of Spread Spectrum Communications Used in UAV Remote Control Systems”, TALLINN UNIVERSITY OF TECHNOLOGY School of Information Technologies, 2017.        